Heterogeneity in ADHD: Neurocognitive predictors of peer, family, and academic functioning

Abstract

Childhood ADHD is associated with impairments in peer, family, and academic functioning. Although impairment is required for diagnosis, children with ADHD vary significantly in the areas in which they demonstrate clinically significant impairment. However, relatively little is known about the mechanisms and processes underlying these individual differences. The current study examined neurocognitive predictors of heterogeneity in peer, family, and academic functioning in a well-defined sample of 44 children with ADHD ages 8–13 (M = 10.31, SD = 1.42; 31 boys, 13 girls; 81% Caucasian). Reliable change analysis indicated that 98% of the sample demonstrated objectively defined impairment on at least one assessed outcome measure; 65% were impaired in two or all three areas of functioning. ADHD children with quantifiable deficits in academic success and family functioning performed worse on tests of working memory (d = 0.68 to 1.09), whereas children with impaired parent-reported social functioning demonstrated slower processing speed (d = 0.53). Dimensional analyses identified additional predictors of peer, family, and academic functioning. Working memory abilities were associated with individual differences in all three functional domains, processing speed predicted social functioning, and inhibitory control predicted family functioning. The current results add to a growing literature implicating neurocognitive abilities not only in explaining behavioral differences between ADHD and non-ADHD groups, but also in the substantial heterogeneity in ecologically valid functional outcomes associated with the disorder.

Working memory and organizational skills problems in ADHD

“…For example, working memory deficits show strong continuity with ADHD inattentive, hyperactive, and impulsive symptoms measured objectively (Kofler et al., ; Raiker et al., ; Rapport et al., ) and by parent/teacher report (Kofler et al., ). This study's working memory tests also show strong convergence with ecologically valid, ADHD‐related impairments in peer functioning (Kofler et al., ), reading comprehension (Friedman et al., ), parent–child relationship quality, academic success/productivity (Kofler et al., ), and organizational skills (current study). That these brief, laboratory‐based tasks with minimal face valid social, academic, or organizational demands show this robust continuity is fascinating, and speaks to the strong association between children's working memory and how successfully they navigate their social and academic worlds.…”

“…Identifying the mechanisms and processes that underlie organization problems is imperative given their chronic, worsening course and adverse outcomes. Organizational problems begin in elementary school for many children with ADHD, and increase in severity as they progress in school (Booster, DuPaul, Eiraldi, & Power, ; Langberg, Molina, et al., ), experience higher workloads (Evans, Allen, Moore, & Strauss, ), and experience increased expectations for personal responsibility from teachers and parents (Meyer, Allison, & Le'Roy, ). These organization problems continue into adulthood (Bikic, Reichow, McCauley, Ibrahim, & Sukhodolsky, ), and portend academic underachievement (Kent et al., ) and lower school grades both concurrently (Langberg, Epstein et al., ) and longitudinally into high school (Langberg, Molina et al., ) – even for intellectually gifted children with ADHD (Leroux & Levitt‐Perlman, ).…”

“…Experimental studies suggest a potential causal role of working memory dysfunction for evoking ADHD-related inattentive and hyperactive behavior Rapport, et al, 2009). Converging evidence also links ADHD-related working memory impairments with ecologically valid, functional outcomes including peer (Bunford, Evans, & Langberg, 2014;Tseng & Gau, 2013) and parent-child relational problems (Kofler et al, 2017). In addition, working memory strongly predicts math (Swanson & Kim, 2007) and ADHD-related reading deficits (Friedman, Rapport, Raiker, Orban, & Eckrich, 2017).…”

Executive Functioning Heterogeneity in Pediatric ADHD

“…The current study addresses these issues, and is the first to simultaneously and comprehensively assess heterogeneity in executive dysfunction among children with carefully phenotyped ADHD using a counterbalanced battery that includes multiple criterion tests per construct (Coghill et al, 2014). Formative indicators of working memory, inhibitory control, and set shifting were derived, and these participant-level component scores were subjected to reliable change analyses (Jacobson & Truax, 1991) that explicitly account for measurement error to objectively define impairment (Kofler et al, 2016;Sarver et al, 2015). We hypothesized that these methodological refinements would produce higher estimates of executive dysfunction than prior studies, such that a majority of children with ADHD would be correctly classified as impaired on at least one of the three primary executive functions.…”

“…Current estimates suggest that only approximately 33%-50% of children with ADHD exhibit impairments in executive functioning (Biederman et al, 2004;Nigg et al, 2005). At the same time, recent critiques of the clinical literature's executive function task selection (e.g., Snyder et al, 2015) question the veracity of these estimates, such that our understanding of executive functioning in ADHD is based, in large part, on data from single tasks that may suboptimally assess their intended construct (Kofler et al, 2016;Coghill et al, 2014;Sonuga-Barke et al, 2008). The neurocognitive heterogeneity observed in ADHD is increasingly recognized as a valid phenomenon (Nigg et al, 2005); however, it is possible that cognitively-informed test batteries with greater construct precision and estimation with multiple tests may allow for the identification of a relatively small number of causal pathways to the ADHD phenotype (Coghill et al, 2005).…”